From viewpoints of being eco-friendly and reducing cost while suppressing materials and waste to the extent possible, there has been known an open-style disposable diaper which is produced by attaching a waist panel material to a rectangular absorbent body including an absorbent member after previously producing the waist panel material having a fastening tape in a separate process. From a viewpoint of fit, it is preferable that the waist panel material is a stretchable member. Generally, the waist panel material is formed by utilizing a stretchable film. However, since a stretchable film is expensive, it is preferable to form the waist panel material by using a so-called thread rubber which is a general member. Here, in a case where a process to obtain a waist panel material using thread rubber and a process to obtain an open-style disposable diaper by attaching the waist panel material to the absorbent body are continuously performed in sequence, a stretchable direction of the waist panel material formed by using the thread rubber generally becomes the same direction as the conveyance direction of the absorbent body, which is a direction perpendicular to a stretchable direction of the waist panel material required while wearing an open-style disposable diaper. Accordingly, in a case of producing an open-style disposable diaper by attaching the waist panel material formed by using thread rubber to the absorbent body in an inline process, the waist panel material formed by using thread rubber is required to be attached to the absorbent body after being rotated by 90°. Since an apparatus to rotate the waist panel material by 90° is required separately, equipment investment is increased.
As a method without using an apparatus to cause the rotation of 90° as described above, for example, Patent Literature 1 discloses a method for producing a stretchable sheet including a process of bonding a threadlike elastic body to a sheet in a state of being stretched while adhesive is applied to a permeable sheet moving in a length direction and the threadlike elastic body provided with tension is translated onto the adhesive applied face along the sheet face of the moving sheet toward the sheet moving direction in a zigzag state and a process of cutting the threadlike elastic body at both ends.
Further, Patent Literature 1 discloses an apparatus for producing a stretchable sheet which fixes a threadlike elastic body to a continuous-length sheet, by using a pair of conveyance belts which include two-tier belts to wind the threadlike elastic body respectively, after rearranging the threadlike elastic body wound around the pair of conveyance belts in a zigzag state in plane view to be parallel by setting a velocity difference between the upper belts and the lower belts.
However, since the two-tier belts in the apparatus using the two-tier belts disclosed in Patent Literature 1 are arranged in a two-tier fashion with a width direction of the both directed to a vertical direction, there is a risk that the threadlike elastic body cannot be stably fixed to a desired state owing to attrition at an upper side of the upper belt or a lower side of the lower belt, causing slipping and the like between the threadlike elastic body.